1. Field of the Invention
The invention relates to a control means as used in apparatus used to electrically heat flowable material dispensed from pressurized containers, such as shave cream.
2. Description of the Prior Art
Apparatus for heating shave cream dispensed from pressurized containers, has been known for some time. Conventional pressurized containers use a propellant gas to discharge foam products therefrom. Generally, the propellant gas is dispersed throughout the product under pressure in a liquified form and, upon actuation of the outlet valve, the propellant forces the product out of the container and, simultaneously, expands to form gas bubbles and thus generate the foam.
Expansion of the propellant from liquid to a gas, however, has a cooling effect on the foam product. This cooling is undesirable because cold shave cream foams are not only uncomfortable, but also slow in softening the beard. Hair is more easily shaved when softened by the penetration of moisture from the shave cream and the softening effect increases at higher cream temperature. Thus, numerous heating devices have been proposed for heating foam shave cream discharged from the containers to increase the ease and effectiveness of shaving. Some previously proposed devices employ electrical resistance elements or wires to supply the heat with a switch operable by the user to control the heating element. When a pressurized container is used it is important that it not be subjected to elevated temperatures which could cause it to burst. Many prior art dispensers do not automatically turn off and, while having a temperature responsive thermostat to deenergize the heating element, some permit the thermostat to continuously recycle which can result in a build-up of temperature transferable to the pressurized container. Also, some prior art dispensers energize the heating element by pressing a button. Excessive temperature rise can occur if the actuation of the button is repeated in rapid succession or is held down to keep it depressed for a long period of time. A thermostatic switch has been designed to avoid these difficulties and is fully disclosed and claimed in patent 3,733,460 while the general arrangement of a heated shave cream dispenser is shown in patent 3,749,880 both of common assignment. The present invention is an improvement on said 3,733,460 patent in disclosing and claiming a combination with an improvement in the control means for heating the dispensed material.